Speedometer drive



Sept.'4, 1928. 1,683,036 v A V. HUG-IES i SPEEDOMETER DRIVE Filed May 29, 1926 Patented Sept. 4, 1928.

UNITED STATES PATENT OFFICE.

VICTOR HUGHES, OF DETROIT, MICHIGAN, ASSIGNOR TO GENERAL' MOTORS RESEARCH CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OF DELAWARE.

SPEEDOMETER DRIVE.

Application filed May 29,

This invention relates to drive means for speedometers, and more particularly to that type of mechanism which transmits the revolution of the propeller shaft of a vehicle to a distantly located indicator.`

The invention is shown and describe-d as applied particularly to automobiles, but it is to be understood that there is no intention to limit the invention to this specific application, and it is obvious that it is equally usable in connection with other forms of traveling vehicles, particularly railway cars, tractors and the like.

The object of the invention .is to provide a cheap, simple but efficientmechanism which will be easy to assemble, positive in operation, and unlikely to get out of repair.

In the drawings,

Fie'. l is a to lan View of a conventional transmission ldrive shaft of an automobile showing the relation of the present speedometer driving mechanism to the drive shaft;

Fig. 2 is a side elevation partly in section of the speedometer driving mechanism; and

Fig. 3 is a transverse section thereof taken on line 3 3 of Fig. 2.

Like parts are indicated by similar characters of reference throughout the vseveral views.

Referring to the drawings, l represents the transmission housing and 2 is the customary universal joint, coupling the propeller or drive shaft 3 with the source of power. The drive shaft 3 revolves within the housing or torque tube 4 and leads to the rear axle, transmitting the propelling power thereto.

The drive shaft has an enlarged portion 3 which is screw threaded at one end. Onto this screw threaded portion 3 is threaded the gear 5, which in this instance is shown as a helical worm gear. The gear 5 is provided with a. lateral extension lflattened on opposite sidesto a'ord an engagement surface for a wrench. A lock nut 7 is shown which secures the threaded worm gear to the drive shaft 3 and insures its rotation therewith. The remaining portion of the enlargement 3 is 'devoid of threads, affording a smooth bearing surface for the bearing sleeve 8. A spacer sleeve 9 is inserted between the bearing sleeve and the torque tube to maintain the drive shaft and tube in spaced relation. The spacer 9 is provided with. an end flange l() which abnts against the end of the ieee. sel-m1 No, 112,628.

torque tube tohold the spacer and bearing in place. l

The housing or case ll, separable into two halves, is clamped about the end of the torque V shaft 13 is recessed for keyed engagement of a finger or pencil (not shown) on the end of a flexible shaft leading to the conventional indicator or speedometer on thedashfboard'. The indicator and connection not forming a part of the invention have not been illustrated. f l

To provide proper lubrication of the drive shaft an oil cup l5 has been shown at the side of the housing in Fig. 3. rithe particular form of oil cup to be lemployed is nonessential.V i l As the vehicle is put into motion and the drive shaft revolves it carries with it the worm gear. 5, which meshes with the gear 14, in turn actuating its integral trunnion shaft and the attached speedometer ldrive shaft, thereby transmitting the drive shaft revolutions to the distantly located indicator on the automobile dash board. y

While in the past speedometers havebeen operated to indicate the drive shaft revolutions, and devices of this general type have become quite common, yet the present invention embodies unique features of compactness and affords a thoroughly practical de` Vice at a comparatively small cost. rlhe invention is directed primarily at simplicity` ease of assembly, and economy of manufacture. Y

Itis to be noted that the separable housing 1l, when clamped in place, besides being a protective encasement for the worm gear, also houses the driven gear, holds the respective parts together, closes off the torque tube to the entrance of dirt and foreign matter, and forms a bearing for the end of the torque tube.

It will be understood that the invention is not to be limited to the exact construction shown, but that various i'nodifications may be used without departing from the spirit or 'los ' scope of the invention, asset forth in the following claims. l

Having thus described my invention,v I

claim:

'1. Speedometea` `actuating means on `the transmission :shaftof an automobile, includ-y ing a helical Worm gear having a lateral eX- tensionwith fiat sides to permit engagement of an adnisting Wrench, screw threads on the interior of the gear for adjustable enga-gement with a screw threaded portion ofthe shaft, and a lock nut on th-e shaft for main-` taining the gear in its adjusted position, `a siecond gear meshing with the Worm gear, and a distantly located indicator connected to the f second gear.

".2, In aA motor vehicl`e,the combination ivith a drive shaft torque tube, a spacer member at the end of the tube, a drive shaft extending thru the tube, having an enlargement thereon, a portion of which is smooth and has bearing in the spacer member, and another portion of which is screw threaded and extends beyond the spacer member, of speedometer actuating means adapted for attachmentas an accessory including av driving gear element-` interiorlyv threaded for engagement with thethreads on i said shaft, a housing separable into two portions and means to clamp said portions about the end of the torque tube Withparts thereof extending beyond the end ofthe tube and en closing said driving ygear element, and a driven gear element having a bearing in one of said portions and housed therein, the axialv clamping, position of said housing on the torque tube serving to locate said gear elements in proper ntermeshing driving rela-4 tion. y i

3. In a motor vehicle, the combination with a drive shaft., a torque tube surrounding the i shaft'and abearing or'the shaft-,at the' end of the tube, of speedometer actuating means adapted for attachment as an accessory, 1n-

. cluding a driving element adapted for thread` edgengagementon the shaft beyond the end of the torque tubeya housing for enclosing said driving element, arranged tobe clamped about the periphery of the torquetube adjaj the shaft, of speedometer actuating VmeansV adapted for attachment as an' accessoryin# cluding a driving elementV havingscrew threaded engagement on the shaft `and being ouV ing relation with the drivingelement bythe provided with portions fortheengagement ofV an adjusting tool,1neans 'to lock said element in its adjusted position, adriven element, and

mountingr means for the `driven 4element secured on the tube `and `adjustable axially thereof to bring the drivenelernent vintodriving relation with the driving element inits locked position ofadjustment.` y l 5, In testimony WhereofI affix my signature.

'wofronynuonns y 

